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Author Topic:   CAM HELP
Dirt Full Roller

Total posts: 68
posted April 04, 2005 07:54 PM  
I have 2 diiferent questions. The first is, will a cam for a 1975 chevy 350 fit into a 1992 chevy 350 or are the cam bearings different sizes?

Second, I bought a Hyd.Crane cam .450/.450 - .218/.218 - 106 5500 rpms using Z-28 springs and stock lifters, I found out the first race it pulls to only about 5000 rpms and quits and am maxing out at 6300. I want to change to .508/.508 - .251/.248 - 106 / 3600 - 7000 Solid Lifter cam, valve lash .030/.030. I have never run a Solid cam, what do I need to do differently to not have any problems. Can I use the same push rods or do I need to make shure they are perfectly fit. I donot have restrictors in the block and realy donot want to pull the engine to put these in if I can get by. What else should I look for? This is for a 9:1 76cc 355 / 3/8 track / 2 bbl. / 6.50 final drive, block has not been decked and heads have not been cut. I have used other Hyd. cams the past 3 years and the engine always maxed out at 6500. Thanks.

[This message has been edited by ARR (edited April 04, 2005).]

Dirt Forum Champ
Total posts: 1019
posted April 05, 2005 06:48 AM  
First, throw out your valve springs and get a set that has about 135lbs of seat pressure and about 350lbs at full lift. Z28 springs are notorious for floating at the rpms you state you're having problems getting past, and a bigger cam will only make it worse.


Dirt Full Roller

Total posts: 30
posted April 05, 2005 08:51 AM  
I wouldn't bother with the restricters as the extra oil is good for the valvesprings (cooling) and the hole in the side of the lifter acts like a restricter anyhow. You need to make sure the valve springs are good because the acceleration ramps on solid cams are much more agressive than on the hyd. cams, and this is what will float the valves if the springs aren't up to the task. Male sure you use polylocks,and your pushrods should work o.k. I try to check my valves on about every fourth night of racing,some guys check them after one night. I think you'd be better off pulling your .050 duration back to 235-240 with the compression you have, and the rpm you max at.Its far better to have not enough cam than just a little too much.

Good luck!!

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